Rectifier filter system



ZAESJ M S FRANKEL REGTIFIE Pill-Tm SIS Pa? filed July 16 19-43;

Patented Apr.- 1, 1947 RECTIFIER FILTER SYSTEM Bills, N. Y., asalgnor to Sidney Frankel, Forest Federal Telephone an York, N. Y.,

I] Radio CorporatiomNew a corporation of Delaware Application July 16,1943, Serial No. 495,056

4 Claims. (01. 175-363) -This invention relates to rectifier filter systerns in which a rectifier is coupled through a filter to a load. In order to obtain good rectifier voltage regulation the filter system must present a high input impedance; and consequently a choke or chokes having a correspondingly high inductance value must be employed. However, when the current drawn from the system changes substantially in a relatively short time, the electrical inertia of the filter inductance seriously affects the shape of the (current output curve. This is especially serious in systems in which the filter output is used for telegraphic keying, in voice or television modulation, or in other arrangements in which the power, is used in the form of pulses.

A The main purpose of the invention is to provide an'arrangement in which a rapidly changing current supply may be drawn from a rectifier filter system without serious distortion caused by the inertia of the filter inductance. This is in general accomplished by replacing the usual choke coil with the primary of a transformer whose secondary is shunted by a resistive load that is reflected in the primary and serves as an impedance to all frequency components of the rectifier and filter circuit except the steady direct current component. V

A more specific purpose is to'provide a system of this type in which the resistance load acrcss the transformer secondary is utilized to obtain useful energy from the system which cthertvise would be wasted. A feature of the invention is the utilization of the transformer secondary to supply energy to a second rectifier Other objects and advantages will the following description, considered in connection with the accompanying drawing, in which,

Fig. 1 is a diagrammatic showing of a rectifier filter system embodying the invention and including a resistance shunted across the transformer secondary; and

Fig. 2 is a diagram of a similar system employ ing a second rectifier and filter system connected to the transformer secondary.

Alternating current from illustrated diagrammatically as generator in, is applied through transformer II to a full wave rectifier l2 whose output is connected across a load It through a suitable filter system illustrated in its simplest form as including inductance It in series and capacitance IS in shunt. The load isindicated as being of the pulsating type by including key IS in series in the circuit, with a bleeder resistor Ilia connected across caa suitable source,

filter system. appear from quired.

pacitor l5. With this arrangement the load I3 will normally be a telegraph system; but of course the showing is purely diagrammatic and it is anticipated that the usual types of filter systems and load connections will be used.

The inductance it constitutes the primary oi transformer ll whose secondary i8 is shunted by a suitable resistance, illustrated as consistin of resistor l9. It will be apparent that the resistance of said resistor will be reflected in the primary It and that the electrical inertia of the latter to rapidly changing currents will be that of a resistance rather than of the usual choke inductance.

However, there" is a certain loss of electrical power in resistor 69; and an arrangement may be provided which will change this loss into a useful load while obtaining the advantages of employing a shunt secondary resistance. This feature is particularly appllcableto conditions which are often encountered, in which another direct current supply of lower voltage that is less critical with respect. to pulse loads is re- In an arrangement of this type illustrated in Fig. 2 a second full wave rectifier 20 is connected across the secondary l8 and the output of the latter rectifier is connected across an other lead 22 through an appropriate filter system illustrated by choice coil is and capacitance 23. in this arrangement, since it would ordinarily requi oth chckein the main circuit and a transi' to provide the secondary supply, there is not only improvement in the characteristic of the pulsating load and economy in the utilisation of the current across the secondary of transformer l, but also certain ad vantages in the required apparatus, since the transformer ll replaces both a choke coil and a transformer.

While two embodiments oi the invention have been illustrated, other modifications may be inconnected across the secondary or said transformer, said resistive load comprising a rectifier system having its input terminals connected to said secondary.

2. A rectifier filter system comprising a transformer, a rectifier and a'load, said transformer having a primary connected in series as a filtering reactance between the output of said rectifier and said load, and a resistive load across the secondary of the said transformer in which said resistive load comprises a rectifier system having its input terminals connected to said secondary,

3. A rectifier filter system comprising a transformer, a rectifier and a load, said transformer having a primary connected in series as a filtering reactance between the output of said rectifier and said load, and a resistive load across the secondary of the said transformer, a capacitor and a resistor connected in shunt across the said first load, the said resistive load comprising a rectifier system having input terminals connected to said secondary.

4. A rectifier filter system as set forth in claim 2 in which said resistive load comprises a filter system.

SIDNEY FRANKEL.

REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 1,946,891 Amann Feb. 13, 1934 2,242,881 Finch May 20, 1941 10 1,835,015 Grouse Dec. 8, 1931 1,712,677 Peter May 14, 1929 1,796,497 Weaver Mar. 17, 1931 1,822,929 Hund Sept. 15, 1931 1,834,820 Bobb Dec. 1, 1931 15 1,969,902 Roberts Aug. 14, 1934 FOREIGN PATENTS Number Country 1 Date 597,109 French Aug. 21, 1925 

